Answer:
2Cu + O2 ----------------> 2CuO
Answer : The correct option is, (D)
Explanation :
Option A reaction : 
It is a combustion reaction. A reaction in which a hydrocarbon react with the oxygen to give product as carbon dioxide and water.
Option B reaction : 
It is a combination reaction. A reaction in which the two or more reactants react to give a product.
Option C reaction : 
It is a decomposition reaction. A reaction in which a reactant decomposes to form two or more products.
Option D reaction : 
It is a single displacement reaction. It is a reaction in which the more reactive element displace the less reactive element. In this reaction, most reactive element chlorine displaces the less reactive element bromine.
Hence, the correct option is, (D)
Answer:
The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive.
balance by putting 2 next to HF
Answer:
Option C :
a chemical formula that shows the relative number of each type of atom in a molecule, using the smallest possible ratio
Explanation:
Empirical Formula:
Empirical formula is the simplest ration of atoms in the molecule but not all numbers of atoms in a compound.
So,
Tha ration of the molecular formula should be divided by whole number to get the simplest ratio of molecule
For Example
C₂H₆O₂ Consist of Carbon (C), Hydrogen (H), and Oxygen (O)
Now
Look at the ratio of these three atoms in the compound
C : H : O
2 : 6 : 2
Divide the ratio by two to get simplest ratio
C : H : O
2/2 : 6/2 : 2/2
1 : 3 : 1
So for the empirical formula the simplest ratio of carbon to hydrogen to oxygen is 1:3:1
So the empirical formula will be
Empirical formula of C₂H₆O₂ = CH₃O
So, Option C is correct :
a chemical formula that shows the relative number of each type of atom in a molecule, using the smallest possible ratio
